Ukraine could charge a Russian tanker captain with causing pollution in the Kerch Strait following a sinking in a storm in December.
Two Russian vessels, the 4,800-dwt Volgoneft 239 (built 1973) and Volgoneft 212 (built 1969), spilled their cargoes into the strait, which links the Black Sea to the Sea of Azov.
The Volgoneft 212 broke up and sank, killing one seafarer.